The following article relates to 2G, 3G and 4G LTE:
What is a reasonable Signal Strength?
For general guide in NB IoT:
- Strong: RSRP ≥ -100 dbm, and RSRQ ≥ -7 dB
- Median: -100 dbm ≥ RSRP ≥ -110 dbm, and -7dB ≥ RSRQ ≥ -11 dB
- Weak: RSRP < -115 dbm, or RSRQ < -11 dBb
In LTE (includes CAT.M1 and NB IoT) signal strength/quality parameters: RSRP, RSRQ, RSSI, SINR and their meaning.
Scholarly white paper on the extra 21dBm advantage CAT.M1 (LTE-M) has over 4G LTE: